Add cache-busting mechanism

.travis.yml

@@ -7,7 +7,15 @@ install: npm i
 script:
 - npm test
 - npm run build
-- npm run clean
+
+  # Remove unwanted files
+- find . -maxdepth 1 -type f  -not -name 'LICENSE' -not -name 'index.html' -not -name 'README.md' -delete &&
+  rm -fr node_modules src dist/vanity.js
+
+  #Cache busting
+- COMMIT=$(git log --format='%h' -n 1) &&
+  sed -i "s/index.js/index.$COMMIT.js/g" index.html &&
+  mv dist/index.js dist/index.$COMMIT.js
 
 deploy:
   provider: pages

package.json

@@ -38,8 +38,7 @@
   "scripts": {
     "test": "node ./node_modules/xo/cli.js",
     "dev": "cross-env NODE_ENV=development webpack-dev-server --open --hot",
-    "build": "cross-env NODE_ENV=production webpack --progress --hide-modules",
-    "clean": "find . -maxdepth 1 -type f  -not -name 'LICENSE' -not -name 'index.html' -not -name 'README.md' -delete && rm -fr node_modules src dist/vanity.js"
+    "build": "cross-env NODE_ENV=production webpack --progress --hide-modules"
   },
   "xo": {
     "rules": {